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Effects of chronic 17β‐estradiol treatment on the serotonin 5‐HT 1A receptor mRNA and binding levels in the rat brain
Author(s) -
Österlund Marie K.,
Halldin Christer,
Hurd Yasmin L.
Publication year - 2000
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/(sici)1098-2396(200001)35:1<39::aid-syn5>3.0.co;2-t
Subject(s) - medicine , endocrinology , 5 ht1a receptor , hippocampus , estrogen receptor , 5 ht receptor , receptor , piriform cortex , receptor expression , serotonin , biology , cancer , breast cancer
Acute 17β‐estradiol treatment had been shown to downregulate the 5‐HT 1A receptor mRNA expression in limbic areas of the female rat brain. The aim of the present study was to determine the effects of chronic 17β‐estradiol treatment on 5‐HT 1A receptor mRNA expression and 5‐HT 1A receptor binding in ovariectomized female rats. Using in situ hybridization histochemistry, no alterations were found on the 5‐HT 1A receptor mRNA levels after the estradiol treatment (2 weeks). Radioligand autoradiographic studies using the selective 5‐HT 1A receptor antagonist [ 3 H]WAY‐100635 revealed reduced receptor binding in the amygdala, hippocampus, perirhinal cortex, and motor cortex after estradiol treatment, whereas no changes were observed in the piriform or retrosplenial cortex. Thus, the previous findings together with the present results indicate that estradiol‐induced alterations in 5‐HT 1A receptor mRNA expression appears within hours, but diminishes with chronic treatment when significant changes on the receptor‐protein level are apparent. The effects of estradiol treatment on the 5‐HT 1A receptor binding in the limbic areas suggest that estrogen can modulate functions such as learning, memory, cognition, emotional processing, and social behavior. Consequently, estradiol modulation of 5‐HT 1A receptor circuits might be a possible pathway for the estrogen influence in the expression of psychiatric and neurological disorders such as Alzheimer's disease, affective disorders, and schizophrenia. Synapse 35:39–44, 2000. © 2000 Wiley‐Liss, Inc.